Here's a collection of vero (stripboard) and tagboard guitar and bass effect layouts that we have put together covering many classic and popular effects in growing numbers. Many of these have been posted on freestompboxes.org, so check that site out for great discussions on building your own effect pedals. Enjoy the builds and please also visit us on Facebook and Twitter

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Friday, 25 July 2014

Skreddy Mayonaise MkIII

The latest incarnation of a very popular classic Skreddy pedal. Thanks to mmolteratx on FSB for the traced schematic.

Info about Marc's original:A faithful recreation of that old-school big box that gave us our startCreamy, sustaining, amp-blowing-up, huge distortion with a grainy, ear-pleasing, low-fi edge and just the right amount of 'hair'Heavy does not have to mean harsh or unnatural or even modernFinally a tone control that is actually useful and powerful, yet does not sound bad at any settingMakes a single-coil pickup sound more like a humbucker, yet doesn't completely obliterate the guitar's toneMakes a clean amp sound like a dirty, cranked amp, even at low volume--preamp or power-tube distortion not required.

The tone of these transistors is nearly identical to the NOS units the original Mayonaise used (they look the same, too). Just a couple of minor capacitor tweaks take it the rest of the way there. Made of the same types of parts as used in our first product ever, which was a sonic clone of the circa 1971 "triangle knob" version fuzz box that used the legendary and unobtainable FS36999 transistors.

Has all that original pillowiness, grit, compression, and near infinite sustain as the original.

I just built the board and now just have to wire it up for testing. I used all carbon comp resistors, multi-layer ceramic caps and NOS SE4021 transistors, so hopefully, it should be a pretty good clone of the original Mayo III.pic of the board:

Great looking build mate. I don't care whether people buy into the mojo or not, but builds using carbon comp resistors always look the dogs bollocks! And I've never had any excess noise when I've used them and the results have always sounded excellent to me.

thanks Mark. and I agree, I think that the carbon comps look cool. i'm not sure that I buy into the 'mojo' of them, but this build does sound incredible, so maybe they do have something to do with it. ;-)

HiI'm a total electronics newbie, but a longtime guitarplayer. And I have been bitten by the fuzz bug.I got my hands on some se4021 but I'm having trouble getting the D5 BAT47.Is there an alternative? (BAT46?), and how does D5 affect sound?

I doesn't affect the sound at all, it's just a reverse polarity protection diode. Try a 1N5817, 1N5818, BAT41, BAT42, BAT85, 1N60P or any other schottky diode you can find. They all have a very similar forward voltage drop and so will have essentially identical results.

Marc tends to use ceramics for the vast majority of the caps. In my Pink Flesh they are mostly the big round ceramics with a few polyesters which I think is the input cap, the two caps at Tone 1 and 3, and maybe the caps in series with the back to back diode pair at Q2 and 3. The larger filter cap is a standard electrolytic.

It depends what your expectations are :o) I like CC builds because they look so cool, and everything I've built with them sounded awesome. But then they would almost certainly also sound awesome if I'd built them with metal film. I think sometimes the tolerance and drift of CCs can get you in a sweet spot of resistance values sometimes, but then the opposite could equally be true and the tight tolerances of metal film could get you in a sweet spot in certain builds.

I think it's nice to have both types and just give things like this a try but whether or not they are worth it is in the eye of the beholder holding the wallet. :o)

Anyone notice the circuit doesn't have lots of volume output? I built mine with a BAT41 and SE4021s from Small Bear. Circuit works and sounds good, but there isn't as much output as I was expecting. Anyone else notice this?

HiI built this with SE4021 from smallbear and 0,5w cc resistors. Yes, it's really crowded....The distortion in this box is really great!!. But the tone knob in my build doesn't do much. I compared the layout to my build several times, but I cant see any mistakes. Fully ccw it has a little more treble, but its barely noticeable.Any ideas to what I've done wrong?

Finally got around to it.Checked the pot, and it's ok. Checked the layout again and again. But cant find any errors. It sounds great but there's no tone control. When listening to the background noise only, and turning tone fully ccw, I can here a little more high end.Any suggestions to what parts I should start replacing?

Your tone pot may have a damaged track. The tone pot is a fairly simple arrangement, check the soldering and values of the resistor and cap connected on the Tone 1 and Tone 3 rows. Knife between all the gaps, because if it isn't working you either have a problem with a part, or a physical error with your build, through maybe a cold joint, unwanted bridge or something similar.

Had some weird problems with this build, as I soldered the negative lead of the 100uf cap wrong, but now it works, including with SE4021's. Sounds great even on my little practice amp. I used a 1N4001 though instead of the BAT47. Don't have any of those, but I could always install a 1N5817 if need be. Then again, should I?

Changed the pot, didn't help.I desoldered the caps at tone 3. Couldn't find any errors, soldered them back, and now it works! I will redo this build though. With the caps I used and the 0,5 w resistors, its a very tight build.But it does sound amazing!

I have a problem with the tone stack. Volume snd gain works as expected but tone adds bass (or cuts trebles) counterclockwise as well as it turns up the volume and clockwise it turns down the volume to zero fully clockwise.

Theres as well a overall Volume attenuation with the pedal on.

Checked solder bridges with multimeter, values, position,...

Im using 2 mpsa18 and other 2 trannies refurbished from an old music device (checked it with atlas tester, both workin BJT NPN hfe~400). I'v tried others as well, 2n3904,... (I hace no high gain right here.)

Some caps are refurbished too the phillips red/orante ones and the multilayer ceramic blue. Could it be the problem?

The Marshall 3005 Lead 12 was a mini-stack with a 12 watt solid state head made in England between 1988 and 1991. People claim it's a gr...

Note

Not all these layouts are verified and some are put together from unverified schematics. So if you have good luck, or bad luck for that matter, then please let me know by dropping a comment in the topic. Thanks.

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